Re: Non-superuser subscription owners

On 2/22/23 14:12, Mark Dilger wrote:
>> On Feb 22, 2023, at 10:49 AM, Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
>> On Wed, 2023-02-22 at 09:27 -0800, Mark Dilger wrote:
>>> Another option is to execute under the intersection of their
>>> privileges, where both the definer and the invoker need the
>>> privileges in order for the action to succeed. That would be more
>>> permissive than the proposed SECURITY NONE, while still preventing
>>> either party from hijacking privileges of the other.
>>
>> Interesting idea, I haven't heard of something like that being done
>> before. Is there some precedent for that or a use case where it's
>> helpful?
> > No current use case comes to mind, but I proposed it for event
> triggers one or two development cycles ago, to allow for
> non-superuser event trigger owners. The problems associated with
> allowing non-superusers to create and own event triggers were pretty
> similar to the problems being discussed in this thread.

The intersection of privileges is used, for example, in multi-level
security contexts where the intersection of the network-allowed levels
and the subject allowed levels is used to bracket what can be accessed
and how.

Other examples I found with a quick search:

https://docs.oracle.com/javase/8/docs/api/java/security/AccessController.html#doPrivileged-java.security.PrivilegedAction-java.security.AccessControlContext-

https://learn.microsoft.com/en-us/dotnet/api/system.security.permissions.dataprotectionpermission.intersect?view=dotnet-plat-ext-7.0

--
Joe Conway
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com